#include"list.h"
list::list() : head(nullptr),tail(nullptr),num(0){}
void list::push(value_ptr e){
    node_ptr p = new node{e,nullptr};
    if(head == nullptr){
        tail = p;
        head = p;
    }
    else 
        tail->next = p;
    tail = p;
    ++num;
}
